Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already establish that this is read-only and non-destructive. The description adds meaningful behavioral context beyond those hints: it reports frame count and real elapsed seconds, handles drop-frame rates, and supports optional rate conversion. No contradictions exist, and the safety profile matches the stated behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single tightly written sentence with no filler. It front-loads the core action, then efficiently covers the optional conversion capability. Every clause earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only calculator with fully documented parameters, the description covers the essential inputs, supported rate families, output concepts, and optional conversion path. There is no output schema, so a bit more detail about return formatting or drop-frame ambiguity could help, but the description is sufficient for an agent to understand what the tool does and what it returns.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and every parameter is individually documented with clear descriptions, enums, and required flags. The description's mention of drop-frame rates and rate conversion reinforces the schema but does not add meaning beyond the structured parameter definitions, so the baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb ('Parse') and a concrete resource ('an SMPTE timecode'), then states exactly what the tool produces: frame count, real elapsed seconds, and optional re-expression at another rate. This clearly distinguishes it from the file-oriented sibling tools (convert_file, inspect_file, list_converters).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description conveys clear usage context: use this when you need to parse, measure, or convert SMPTE timecodes. It mentions the optional conversion behavior via 're-express it at another rate,' and the schema further defines modes. However, it does not explicitly name alternatives or state when not to use it, though the siblings are not plausible substitutes.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.